Electric aircraft have significant advantages over fossil-fuel powered conventional aircraft. For example, electric aircraft can achieve the same horsepower at any altitude, whereas fossil-fuel powered aircraft lose substantial power at higher altitudes due to low oxygen levels. Electric aircraft are capable of generating instantaneous torque at low RPM. Still further, electric aircraft have zero emissions, a low noise output, and low heat generation, all of which are particularly advantageous in military applications, where low noise and heat levels in particular enhance the stealthy characteristics of the aircraft, thus allowing the aircraft to more effectively avoid enemy detection and attack.
Civilian and commercial operators also benefit from the advantages associated with electric aircraft. For example, electric aircraft are upwards of 90 percent efficient, compared to fossil-fuel powered aircraft which are roughly 35 percent efficient. Thus, electric aircraft may be less expensive to operate than fossil-fuel powered aircraft, especially in light of the ever increasing cost of fossil fuels. As stated above, electric aircraft have zero emissions and a low noise output. Electric aircraft are, therefore, environmentally friendly. This alone has the potential of opening up new flight operation opportunities in noise abatement zones and environmentally protected areas as well as complying with future pollution and emissions mandates.
Of course, there are drawbacks associated with electric aircraft, particularly electric aircraft that operate on battery power. The primary drawback is range. An electric aircraft operating on battery power is severely limited in range, that is, the distance an aircraft can travel without having to land and refuel, or recharge in the case of electric aircraft. This problem is primarily due to limitations associated with the current state of battery technology.
Current state of the art batteries have very low energy densities compared to, for example, gasoline. Indeed, the large energy density gap between fossil fuels and batteries is impeding the widespread adoption of electric vehicles, including electric aircraft. Present state of the art electric aircraft are barely able to achieve ranges of 200-300 miles before having to land for a long period of time to recharge the onboard battery.
Electric automobiles (including hybrid automobiles) are designed to recapture braking energy. Kinetic Energy Recover Systems (KERS) are known in the art and used for recapturing the braking energy of a ground vehicle in order to partially recharge the battery during use. This, in turn, increases the number of miles electric automobiles, motorcycles, and other such ground vehicles can travel without recharging. Although it is possible that some energy could be recovered by an electric airplane such as during descent, electric aircraft do not have the same level of braking energy to recapture; thus, electric aircraft have not been able to achieve acceptable range compared with their fossil fuel powered counterparts, the same way electric cars are beginning to achieve some level of acceptable range compared with their fossil fuel powered counterparts.
Another drawback associated with electric aircraft is cost. Current state of the art batteries are very expensive. Moreover, manufacturers of electric airplanes typically utilize the best batteries on the market in order to realize the best possible range performance. These batteries are naturally the most expensive batteries and in some cases, are more prone to failures and safety concerns such as onboard fires.
On a positive note, battery technology is rapidly improving. However, it is not improving at a rate that is likely to allow electric airplanes to achieve any sort of performance parity with gasoline or jet fuel powered counterparts, and become a practical reality, any time in the near future. Accordingly, what is needed is an electric aircraft and/or a method of operating an electric aircraft that is capable of meeting or exceeding the range performance of gasoline or jet fuel aircraft, without a complete reliance on battery technology to close the range gap.